Photographic development of color on textile and other materials



Patented Dec. 30, 1952 UNITED STATES PATENT OFFICE PHOTOGRAPHIC DEVELOPMENT OF COLOR ON TEXTILE AND OTHER MATERIALS No Drawing. Application June 28, 1949, Serial. No. 101,917. In Great Britain July 1A, 1948,

5 Claims.

It is known to decorate textilefabrics in colour by processes employing exposureto alight source as the primary means of ultimatefixation of colcuring matter onthe material. Thus, a gelatinebichromate, solution may be applied locally, e. g. by printing, to a textile fabric and after drying the material may, be exposed to light, which brings about deposition of the chromium in a form capable of reacting withmordant dyestuffs, which reaction is utilised to producethe design in colour. If the gelatine-bichromatesolution be applied all over the cloth, and a stencil or photographic negative placed between the prepared fabric and the light source, and the exposed cloth washed to remove the bichromate-gelatine in the unexposed parts, and then subsequently dyed with a mordant colour, a coloured pattern effect corresponding to the, exposed parts is produced,

Instead of preparing in gelatine-bichromate and developing in a dyestuff subsequent to exposure to light, the colour, may be produced directly on the fabric by impregnating with the sulphuric ester of a leuco vat dyestuff; On exposure to light, the vat dyestuii is regenerated in proportion to the amount of light falling on the sensitised material.

Some processes utilise light-sensitive diazo compounds. Thus, one mayv utilise the destructive power of light on the diazo group as in the diazotype process, where cloth is prepared for example in a diazotised solution of p-amino-diphenylamine and after exposure to light, treated in a solution of a coupling; component such as pheoroglucinol-or B-naphthol', when colour is developed on the unexposed portions of the material only.

On the other hand one may utilise the power of light to convert a stable diazo compound into the active form capable ofcoupling with phenols etc; thus, cloth may: be impregnated with an aqueous alkaline solution containing p-naphthol together with the sodium salt of the anti-diazo sulphonate of benzene. On drying and exposing to light, colour is developed in proportion to the light falling on the sensitised material.

Methods have been proposed whereby such photographic processes can be employed to produce multicolour or natural colour prints (as in the triecolour process) whereby a more or less complete gamut of shades can be built up from the three subtractive primaries; for example it has been proposed to sensi ise for the firstcolour, expose to light, wash out all the unreacted chemicals, resensitise for the second colour, expose and wash again and then sensitise and expose for the third colour. The principal disadvantageof such a process is that unless the material isrigid, the dimensional changes which occur on washing between the exposures, make exact registrationof the colours impossible.

To be successful, any multi-colour process must permit of the colours being applied exactly in register with one another, and the object of the present invention is to provide a multi-colour process which complies with this requirement.

The invention comprises a process for the decoration of sheet material such as textile fabrics or paper with two or more colours to produce a design or picture made up of compound shades of the said colours, in which the material to be decorated is alternately: treated with light-sensitive compositions, and exposedto light, the conditions being such that during the second and subsequent exposures, development of colour is restricted to the light-sensitive composition last applied. To achieve this end, use may be made of light-sensitive compositions forthe second and subsequent applications which contain some ingredient capabl of preventing further development of colourin the previously applied lightsensitive compositions, or a substance which serves to prevent further colour formation may be applied separatelyinstead. of being actually part of the light-sensitive composition. A feature of the invention is that it does not necessitate washing of the material, between successive exposures and therefore the materialcanbe held, from the time of commencement of thefirst exposureto light, to the. completion of thellast, in such a way that shrinkage, extension, or other late eral movement of the material cannot take place.

Under the term development of colour We include oxidation promoted by light, as with the sulphuric esters of leuco vat dyes; coupling of stabilised diazo compounds with naphthols etc. under-the influence of light, and photochemical reactions resulting. in the fixation of a. mordant which may then be dyed. with suitable dyestuffs. In these cases the exposure to: light is, made through a negative mask. Wealsoinclude in the term development of colour theindirect development. of colour. in which. for example a di-azo compound is destroyed and the colour is subsequently produced byv reacting the undestroyed portion with a coupling component- In this case the exposure to light, is made. through. a positive mask.

n carr n u the pro ess, o our inventi n. We ight find t Qonven r producin the or mor c u s equ m. 1 o uild. up the pattern or picture, to make use of dyestuffs from the different chemical classes known to be capable of development by photo-chemical action. Thus in a tri-colour production we might find it advantageous to use three dyestufi classes and the finished print might for example contain a mixture of vat, chrome mordant and insoluble azo dyestuffs.

In general we prefer to use the sensitising chemicals in aqueous solution, but it is sometimes advantageous to incorporate water-miscible solvents such as ethyl alcohol, ethylene glycol, tetrahvdrofurfuryl alcohol, di-ethylene glycol monoethyl ether. thiodiglycol etc. as aids to solution. Hygroscopic agents such as glycerol or urea may also be added where humid conditions are desired for the photo-development of the colours. In order to minimise time exposure to the light source it is sometimes advantageous to incorporate in one or more of the sensitlsing solutions a catalyst such as the oxidation catalysts used in fixing colours in ordinary calico printing processes, for example copper or cerium salts. The sensitising solutions, thickened if desired, may be applied to the material by any suitable method such as printing, spraying, brushing and the like. The first sensitising process may con veniently be carried out on a mangle or other suitable impregnating machine.

It is not necessary to work in the dark, but it is preferable in order to avoid any undesirable colour development to work in diffused or other form of light of reduced actinic power. For actual colour development in the production of a pattern or picture, exposure may be to natural daylight, but preferably some artificial high intensity light source, such as a carbon arc, is used.

On or after application of the first sensitiser, the material is stretched to the desired dimensions, and precautions are taken to maintain it at these dimensions during subsequent operations. The material may for instance be fixed on a frame by means of pins, clips, or other holding devices, or it may be held in place by frictional forces, pressure, or suction. In order to facilitate correct registration, the material may be stiffened, or may be fixed on a rigid substratum by means of an adhesive.

The second and/or subsequent sensitiser may intrinsically be capable of preventing further colour development in a previous sensitiser by reason of the chemical or physical properties of one or more of its constituents. Thus, a sensitising composition consisting of an aqueous alkaline solution of the sodium salt of an anti-diazo-sulphonate and a coupling component will prevent further development of colour in the case of the sulphuric ester of a leuco vat dye by reason of the alkalinity of the solution. Other suitable substances which will prevent further colour de velopment in the case of the sulphuric esters of leuco vat dyes are etherifying agents such as dirnethylphenylbenzyl ammonium chloride, mild reducing agents such as soluble sulphites, thiosulphates etc. For preventing further coupling in a mixture of an antidiazo compound and a coupling component, reducing agents such as sulphites and excess caustic alkali are among the substances suitable. If one of the stages employs for example the decomposition of a diazo compound by light, the subsequent treatment with a naphthol serves the dual purpose of developing the azo colour and reventing any further modification of azo colour on subsequent exposure.

Example 1 A cotton cambric is impregnated by padding with a 4% aqueous solution of the sodium salt of the disulphuric ester of leuco-4.4 dimethy 6.6-dichloro-thioindigo, stretched on to a frame, and fixed in position with pins. It is then dried at a temperature of 20 C. in light of reduced actinic power, and afterwards exposed to light through the red printer of a set of tricolour negatives. The cloth is now sprayed with an aqueous alkaline solution containing 2% of 2-sodium diazo sulpho 4 chloro toluene and 1.5% of di-aceto-acetic o-tolidide and dried. This serves simultaneously as the yellow sensitiser and red desensitiser. Exposure is now made through the yellow printer and then the blue sensitiser is applied by spraying with an aqueous solution containing 6% sodium chromate, 0.5% sodium hydroxide, sodium thiosulphate and sodium sulphite. After drying as before the final exposure is made with the blue printer. The fabric may now be removed from the frame and is well rinsed in cold water, soaped at the boil for 5 minutes and finally dyed with the mordant dyestulf Chromazurine G (Colour Index No. 879). After the completion of dyeing, the cloth is rinsed, given a light soaping, rinsed and dried, when it is found that the three superimposed colours red, yellow, and blue have blended to build up the desired coloured picture.

Example 2 A. viscose taffeta cloth is prepared by padding in a 2% solution of the sodium salt of the disulphuric ester of 5.7-5.7-tetrabromo-indigo containing 0.1% copper acetate as an oxidation 3 catalyst, stretched onto a frame, fixed in position with pins and dried at a temperature not exceeding C. The prepared cloth is now exposed through the blue printer of a set of tricolour negatives and immediately afterwards an aqueous alkaline solution containing 1.5% of 2 hydroxy-S-naphthoic-Z.l-dimethoxy-5-ch1oranilide and 2% of 2-sodium diazo-sulpho-G- chlorotoluene suitably thickened is applied by screen printing all over the area of the final picture. After drying as before, exposure to light is made through the red printer. Now the yellow sensitiser is applied by screen printing a thickened aqueous solution containing 6% sodium chromate, 1% sodium hydroxide, 7.5% sodium thiosulphate and 20% potassium sulphite. The cloth is now dried and exposed to light through the yellow printer and then washed as in Example 1. It is now dyed with Persian berry extract (Colour Index 1234) and finally rinsed and soaped as in Example 1.

Example 3 A cotton weft sateen is impregnated on the mangle with a 2% solution of the sodium salt of the disulphuric ester of leuco 5.7-5.'l-tetrabromo-indigo, stretched on a frame and fixed in position with pins, being then dried so as to contain 15% moisture, and exposed to light as in Example 2. The cloth is now sprayed with a 12 aqueous solution of the sodium salt of dimethylph-enyl-benzyl ammonium chloride-disulphonic acid and dried. This serves to prevent further development of the blue in the first sensitising composition. A solution containing 4% of the sodium salt of? the? disulphuric' ester of diphenyl 1.2-5.6-anthraquinone-dithiazole, 15% tetrahydrofurfuryl' alcohol and 0.1% copper acetate is then sprayed on and the cloth dried so as to retain 6% moisture and afterwards exposed to light through the yellow printer. Finally an aqueous alkaline solution containing 1.5% Z-hydroxy-3-n'aphthoic anilide and 2% of 2-sodium diazo sulpho chlorotoluene is applied by spraying and after drying the cloth is exposed to light through the red printer, removed from the frame, Well rinsed in cold water, soaped at the boil, rinsed and dried.

Example 4' A 100% viscose satin fabric is wet with water, squeezed, stretched onto a frame and dried while held onto the frame with pins. This ensures that dimensional changes will not take place on application of any of the sensitising solutions. The cloth is now sprayed with a 5% aqueous solution of the sodium salt of the disulphuric ester of diphenyl-1.2-5.6 anthraquinone-dithiazole and dried at low temperature, being then exposed through the yellow printer of a set of tricolour negatives. It is now sprayed with an aqueous alkaline solution containing 1.5% Z-hydroxy-S- naphthoic-o-toluidide and 2% of sodium diazosulpho 4 benZoyla-mino 2.5-diethoxybenzene and after drying as before exposed to light through the blue printer. The exposed print is next sensitised by spraying with an aqueous solution containing 4% potassium chromate, 1% potassium hydroxide, 4% potassium thiosulphate, and 20% potassium sulphite, and after drying exposure to light is made through the red" printer. The fabric is removed from the frame, washed as in Example 1, and then dyed with Novochrome Brilliant Red R (a chrome mordant dyestuff marketed by Durand and Huguenin SA, Basel, Switzerland) and after dyeing, rinsed, soaped lightly, rinsed and dried as in Example 1.

In the method described in the above examples, the fabric is stationary and the process discontinuous. It is also possible to carry out the whole or part of the process in a continuous manner, by passing the fabric through sensitising, drying and exposing devices in the correct succession.

What we claim is:

1. In the production of tri-color prints on textile fabrics, paper and the like, the process which comprises applying to the material to be decorated a composition containing a sulfuric ester of a leuco red vat dye as a ligh -sensitive component, fixing the dimensions of the material, exposing the so-treated material to light through the red printer of a set of tri-cclor negatives, then without washing treating the material with a composition containing an alkali to desensitize the undeveloped portion of the said sulfuric ester, a salt of an anti-diazo-sulfonate and a coupling component capable of forming a yellow dye therewith, exposing to light through the yellow printer, then without washing treating the material with a reducing agent to desensitize the undeveloped yellow color and a chemical adapted to form a mordant on exposure to light, exposing to light through the blue printer and then washing and dyeing with a blue mordant dyestufi capable of uniting with said mordant.

2. In the production of tricolor prints on textile fabrics, paper and similar base materials, the process which comprises applying to the base maa sulfuriaester. of aleuco vatidyeof one. 01'. the: colors, red,. blue and yellow? as. a. lightlsensitive component, fixing the. dimensions. of the material and exposingt'olight. throughone of. a. set of tricolor negativescorrespondingtothe color of said dye, thenwithoutwashing treating the material witha. composition. containing. an. alkali. to desensitizethe. undeveloped. portion of. the. said sulfuric ester, a salt. of an anti-diazoisulfonate and acoupling component capable of forming therewith adyeof' another of thecolors red, blue and yellow, exposing to light through the corresponding tricolor negative, then withoutwashingtreating. the material with a, reducing agent to. desensitize the undeveloped anti-diam sulfonate. and a water'soluble chromate, exposing to light through thethird tricolor. negative and then washing and dyeing with a mordant dyestuff of the remainin color of the colors, red, blue and yellow capable of uniting with the mordant formed by exposure of the soluble chromate to light.

3. In the production of tricolor prints on textile fabrics, paper and similar base materials, the process which comprises applying to the base material to be decorated a composition containing a sulfuric ester of a leuco vat dye of one of the colors red, blue and yellow as a light sensitive component, fixing the dimensions of the material and exposing to light through one of a set of tricolor negatives corresponding to the color of the dye, then without washing treating the material with a composition containing an alkali to desensitize the undeveloped portion of the said sulfuric ester, a salt of an anti-diazo sulfonate and a coupling component capable of forming therewith a dye of another of the colors red, blue and yellow, exposing to light through the corresponding tricolor negative, then without washing treating the material with a composition containing a, compound to desensitize the unreacted coupling component, a. further coupling component not rendered inactive by said compound, together with the same anti-diazo sulfonate capable of forming therewith a dye of the remaining color of the colors, red, blue and yellow, exposing to light through the third tricolor negative, washing and drying.

4. In the production of tricolor prints on textile fabrics, paper and the like, the process which comprises applying to the material to be decorated a composition containing a sulfuric ester of a leuco vat dye of one of the colors red, blue and yellow as a light sensitive component, fixing the dimensions of the material and exposing to light through one of a set of tricolor negatives corresponding to the color of the dye, then without washing treating the material with a desensitizing etherifying agent and then with a solution containing a sulfuric ester of a leuco vat dye of another of the colors red, blue and yellow, exposing to light through the corresponding tricolor negative, then without washing treating the material with a composition containing an alkali to desensitize the undeveloped portion of said second sulfuric ester, a salt of an anti-diazc sulfonate and a coupling component capable of forming therewith a dye of the third of the colors red, blue and yellow, exposing to light through the third tricolor negative, washing and drying.

5. In the production of tricolor prints on textile fabrics, paper and similar base materials, the

. reducing agent and a substance adapted to form :a mordant on exposure to light, again exposing to light in selected areas only and subsequently dyeing with a mordant dyestufi; the dyes and coupling components being so-chosen that a different color is developed in each of the dyeing steps and that a tricolor print results.

FRED ISHERWOOD.

WILLIAM STUART MILLER.

8 REFERENCES CITED The following references are of record. in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,623,123 Lage Apr. 5, 1927 1,710,455 Langguth et a1 Apr. 23, 1929 1,841,653 Van der Grinten Jan. 19, 1932 1,997,507 Akintievsky Apr. 9, 1935 2,200,018 Bertrand May '7, 1940 FOREIGN PATENTS Number Country Date 290,010 Great Britain Jan. 15, 1930 

1. IN THE PRODUCTION OF TRI-COLOR ON TEXTILE FABRICS, PAPER AND THE LIKE, THE PROCESS WHICH COMPRISES APPLYING TO THE MATERIAL TO BE DECORATED A COMPOSITION CONTAINING A SULFURIC ESTER OF A LEUCO RED VAT DYE AS A LIGHT-SENSITIVE COMPONENT, FIXING THE DIMENSIONS OF THE MATERIALS EXPOSINT THE SO-TREATED MATERIAL TO LIGHT THROUGH THE RED PRINER OF A SET OF TRI-COLOR NEGATIVES, THEN WITHOUT WASHING TREATIAG THE MATERIAL WITH A COMPOSITION CONTAINING AN ALKALI TO DESENSITIZE THE UNDEVELOPED PORTION OF THE SAID SULFURIC ESTER, A SALT OF AN ANTI-DIAZO-SULFONATE AND A COUPLING COMPONENT CAPABLE OF FORMING A YELLOW DYE THEREWITH, EXPOSING TO LIGHT THROUGH THE YELLOW PRINTER, THEN WITHOUT WASHING TREATING THE MATERIAL WITH A REDUCING AGENT OT DESENSITIZE THE UNDEVELOPED YELLOW COLOR AND A CHEMICAL ADAPTED TO FORM A MOIRDANT ON EXPOSURE TO LIGHT, EXPOSING TO LIGHT THROUGH THE BLUE PRINTER AND THEN WASHINGAND DYEING WITH A BLUE MORDANT DYESTUFF CAPABLE OF UNITING WITH SAID MORDANT. 